There are several musical apparatuses conventionally known in the art for teaching or aiding a trainee to play a musical instrument. For example, unexamined Japanese patent publication No. H06-067653 describes an electronic musical instrument which generates musical sounds with different sound effects imparted according to the correctness of the player's key depressing operations (manipulations) as the player plays a melody on the instrument following an automatic accompaniment or a melody guide. Unexamined Japanese patent publication No. 2000-288254 describes a game device which displays on a screen playing time instructions so that a player plays an electric guitar following the instructions, and then the device computes the time differences between the instructed times and the played times and displays on the screen the computed time difference for every instructed time. A further example is unexamined Japanese patent publication No. 2005-21655 (corresponding to unexamined US patent publication No. 2005/0096132 A1) which describes a music game system wherein indication objects are displayed on a monitor screen at the time intervals in agreement with the rhythm of music so that the player can generate musical tones in synchronism with the given music by striking the strike surface of the game console.
There is also known an electronic percussion musical instrument which gives an automatic accompaniment or a ticking tempo guidance for training a player to strike a percussion head at correct timing, wherein the trainee can selectively set a tolerance time range for evaluation, and the instrument evaluates the correctness of the trainee's strike time points in reference to the set tolerance and displays the evaluation result.
In the above mentioned electronic percussion instrument, however, the tolerance range is set by the trainee, and thus the once set tolerance range may become too wide for a trainee who has increased his/her ability or may become to narrow for a trainee who has decreased his/her ability. In either case, the trainee has to readjust the tolerance range by evaluating his/her own ability. It will be not easy to evaluate his/her own ability with some accuracy, and it will accordingly be not easy to set a correct tolerance range for his/her training. And further, a disadvantage may be that the trainee has to interrupt training to readjust the tolerance setting in the middle of the training, as the playing ability changes during the training.
Further, in the above mentioned electronic percussion instrument, the tolerance range is set with the same margins before and after the correct timing point, and thus such a training instrument may be useful for a trainee whose timing correctness is apt to be unstable in both sides, i.e. before and after the correct timing.
But many trainees have a tendency of striking the percussion head with a time deviation in either one direction from the correct timing, i.e. before the correct timing or after the correct timing. For such a trainee having a general tendency of one sided time deviation, such a training instrument will serve a half of the function.